If you are reading this then you must be experiencing an interaction between
Clipper's VMM (Virtual Memory Manager) and your operating system, or you are
receiving a DOS Error 4 at run time.  Don't despair!  This is not a bug in
Zachary.  The answer is to configure your machine to recognize Clipper's need
for environmental settings.  Here is what you can do:

- If The ZACH1.EXE Appears To "Freeze" At Runtime

Zach1.EXE is compiled with Clipper 5.01 and linked with Blinker 2.01.
This means that Zach1 wants EMS memory. Depending on your machine
setup you may find Zach1 hangs up or freezes under certain conditions.  In
order to achieve this you'll need to make sure there is EMS available for
Zach5. This means removing the SET CLIPPER=E0 from your DOS environment if
you have one set in your Autoexec.bat.  Once you do this, reboot your machine.

- If This Does Not Solve Your Problem, Or You Did Not Have The Clipper=E0
  Setting * OR * You Are Experiencing DOS ERROR 4

Clipper wants to see certain environmental settings whenever a Clipper-compiled
application is run.  The following settings, added to your Autoexec.bat file
should work for you:

SET CLIPPER=SWAPPATH:'C:\SPOOL' //TEMPPATH:'C:\SPOOL' //F99 //BADCACHE

Here is an explanation of the switches:

SWAPPATH:  This tells Clipper where to store parts of the application's
internal overlays that it needs to swap in and out of memory.  Note that
the word SWAPPATH is followed by a colon and then a drive and path name
that is surrounded by single quotations.  The drive and directory MUST
exist.  The use of quotes is also required.  I use C:\SPOOL on my machine.
The actual name on your machine can be different.


TEMPPATH:

This tells Clipper where temporary files will reside.  It can be the same
as your SWAPPATH statement.

F99  This tells Clipper how many file handles it may open and use.  99 is a
very high number and you will not normally need to set it that high.  At
any rate, the number may not be higher than the maximum setting in your
Config.sys.  If you are getting a DOS Error 4 when running Zachary, you do
not have enough file handles available.  Check the settings both in Config.sys
and in your Autoexec.bat file.  Make any required changes and reboot.

BADCACHE is not normally required and is only added when a Clipper application
conflicts with your disk cache program.


- If You Still Have A Problem -


The Blinker 2.01a overlay manager respects the BLINKER envrionment
variable. The following settings may cure the problem:

  SET BLINKER=/OP1 /OU1 /CX512

Here is a definition of the switches:

/OU1      Enable use of UMBs for overlays  
/OP1      Enable use of EMS for Overlays
/CE512    use EMS for overlay caching
/CX512    use XMS for overlay caching

You may use one or all of these switches.  We suggest that you try
it with none and then add them one at a time to see what works.

On my machine the optimal setting seems to be:

  SET BLINKER=/OP1 /CX512

- If All Else Fails -

Please, call us at  (617) 551-0858.  We'll help you out.

Len Dozois
Zachary Software, Inc.


